This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
The Bombardier beetle defends itself by blasting an explosive and toxic stream of hot water and chemicals at its enemies. But how could such a dangerous defense have evolved without killing the beetle itself?
The answer may lie in how the beetle's chemical cannon stores the ingredients for the toxic brew, and in the fuse that ignites the chemical reaction that creates it. In the beetle's abdomen are two parallel glands containing a stable and harmless mix of hydroquinones and hydrogen peroxide. Some types of beetle store stinky versions of hydroquinones in sacs under their shells to make them unpalatable to predators. But the bombardier beetle’s glands evolved for a more nefarious purpose. When the mixture of hydroquinones and hydrogen peroxide flow into a sac connected to the outside world,they encounter peroxidase enzymes, which act as a fuse. The hydroquinones are converted into a toxic type of quinone in a reaction that generates a lot of heat, and explodie out of the abdomen in a hot, toxic squirt.
It all happens in a fraction of a second, but this high-resolution, slow-motion video lets you watch the whole thing unfold.
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